Question

You have 64 grams of a radioactive kind of argon. How much will be left after 4 hours if its

half-life is 2 hours?
grams

Answer 1

You will have none left because a half life is half of the time it takes to decompose. If the total time is double the half life, it will have completely decomposed by the end of the total time.

Answer 2

16 gram

Step-by-step explanation:

times it ionises/decays =
`(4)/(2)` = 2 times

we will divide by 2, two times, because it decays two times.

Left after 4 hours: 64 ÷ 2 ÷ 2 = 16 gram

OR

By using the formula:
`(m)/(2^(n) )` .....where m is the mass and n is times it decays.

times it decays: 4 ÷ 2 = 2 times

Left after ionising:
`(64)/(2^2)` = 16 gram.